EART 2 Lecture Notes - Lecture 21: Squall, Silt, Bed Load
Document Summary
Caused by collision of air masses heated/cooled differently by surface of the earth. North america: warm, wet, winds from gulf of mexico, flow north, collide with cold, dry air from rocky mountains. Tornado = instability produced by horizontal movement of mass in upper atmosphere center region of low pressure, surrounded by high pressure. People killed by flying debris, collapsing structures. 2011 worst year for tornado fatalities in u. s. (553) since 1925 (794) Mile wide ef 5 tornado, 158 fatalities, . 8b of damage. Wind circulation, driven by air pressure differences, transports particles of dust and sand, as well as water over the surface of the earth. Particles move by drag of the wind, resisted by gravity. Small particles (silt and clay), affected by wind turbulence, move long distances, can rise high suspension load . Big particles (sand and bigger) move only short distances, near ground, as bedload . Comes over sierra nevada, spills into central valley.
